Monoazo dyestuffs



Un t d Sta Patent O fi c 8 Claims. -(Cl. 260-'196) The inventionconcerns monoazo dyestuffs containing neither sulphonic acid norcarboxylic acid groups,.which are suitable for the dyeing of wool andsimilar natural and synthetic fibres in pure, fast-to-light orange tored shades. It also concerns processes for the dyeing of these fibresusing the new dyestuffs and, as industrial product, the materialfast-dyed with the aid of these dyestulis.

It has been found that valuable monoazo dyestuffs are obtained if thediazo compound of an amine containing no sulphonic acid and carboxylicacid groups of the general Formula I wherein A represents a radical ofthe benzene or naphthalene series and B represents a benzene radical,

whereby the amino group must be in the ortho position to a sulphonylsubstituent, is coupled in an acid medium with a Z-aminonaphthalenecompound having no sulphonic acid and carboxylic acid groups whichcouples in the l-position, of the general Formula II wherein Xrepresents H or OH, and Y represents a:

amines as well as sulphonic acid aryl ester groups; the cyano group;carboxylic acid ester groups; halogens.

Radicals of the benzene and naphthalene series are used as aromaticradicals A. A can be for example the radical of a benzene sulphonicacid, of a toluene or xylene sulphonic acid, of a cymol sulphonic acid,of a monoor di-halogenbenzene sulphonic acid, of a halogen alkylbenzenesulphonic acid, of a naphthalene sulphonic acid, of a diphenyl sulphonicacid, of a tetrahydronaphthalene sulphonic acid.

Diazo components used according to the present invention contain as thebenzene ring B advantageously the radical of aZ-aminobenzene-l-sulphonic acid, for example the radical of a 4- orS-halogen-Z-aminobenzenel-sulphonic acid, of a 4-alkyl or4-alkoxy-2-aminob enzene-l-sulphonic acid, of a 4- orS-acylamino-Z-aminobenzene-l-sulphonic acid, of a 4- or S-alkyl or arylsulphonyl-Z-aminobenzene-l-sulphonic acid. The benzene ring B can alsobe derived, however, from a 3- amino-4-arylor -alkylsulphonylbenzene-l-sulphonic acid, a 3-amino-4-sulphonic acid arylester-benzene-lsulphonic acid, or a 3-amino-4-sulphonic acidamidebenzene-l-sulphonic acid.

The diazo components used according to the present invention areobtained by known methods by reacting in a weakly alkaline mediumsuitably substituted aryl or alkyl sulphonic acid chlorides with.solutions of the alkali metal salts of suitably substituted arylsulphonic amides while reducing the nitro groups to amino groups orsaponifying acylomino groups.

The diazo components are diazotised advantageously by the indirectmethod by dropping aqueous solutions containing the alkali metal saltsof the diazo components 1 hydroxyl sulphonyl substituent selected fromthe group consisting of SO -alkyl, SO -aryl, SO -O-aryl and SO Rradicals, wherein R represents a secondary amino group. Valuabledyestufis according to the present invention are derived chiefly fromdiazo components of the For-.

mula I in which the amino group is in the o-position to i thedisulphirnide group. It can, however, also be in the o-position toanother sulphonyl substituent. In the particularly valuable dyestutfs, Yin Formula II represents the lower alkyl phenyl group. Also diazocomponents in which the radical ,A represents either the unsubstitutedor the chloro or methyl substituted phenyl radical produce the mostvaluable dyestufis: j 1

The aromatic rings, in particular A and B, in the dyestufis according tothe present invention can contain, for example, the followingnon-ionogenic substituents: alkyl groups such as the methyl, ethyl, nort-butyl group; trifluoromethyl group; 1.2-alkylene groups such.

and the necessary amount of alkali nitrite into cold excess mineralacid..

In the coupling components of the general Formula II, the peripositionto the coupling canbe either free or substituted. The sulphonylsubstituent Y ..should not dissociate acid/in water, that is should not40 be a sulphonic acid or an acylated sulphonic acid amide group; itshould never, i.e. even in an alkaline medium at a higher pH value, be asalt-forming sulphonyl substituent, that is for example an alkyl; oraryl sulphonyl group, a sulphamide group derived from a secondary amine,e.g. a dimethyl, diethyl, dibutyl, N-methyl-phenyl, N-ethyl-phenyl,N-butyl-phenyl, dicyclohexyl amide group or a sulphonic acid arylestergroup, eg the sulphonic acid phenyl ester, methylphenyl ester orchlorophenyl ester group. If X is the hydroxyl group, then Y isadvantageously in the 6-position.

Thus, azo components used according to the present invention are forexample, derivatives of Z-aminonaphthalene-5-, -6- or -7-sulphonic acidand 2-amino-8- hydroxynaphthalene-6-sulphonic acid as defined above.

The coupling is performed in acid, preferably aqueous organic solution.For example the azo componets are dissolved in concentrated lower fattyacids with the addition of lower alcohols and possibly mineral acid,

. lower ketones or amides of lower fatty acids and mixed with theaqueous solutions or pastes of the diazo compounds. On completion of thecoupling, water is added to dilute, any organic solvent is removed withsteam and the colour salt is isolated with sodium chloride.

The new dyestuffs are orange to red powders which generally dissolveeasily in hot water with the corresponding colour and which dye wool andsimilar natural and synthetic fibres such as silk, lanital, polypeptideand polymethane fibres from a neutral to weakly acid bath in pure orangeto red shades which are fast to light and wet.

The new dyestuffs are very suitable also for the printing of textiles.They are particularly suitable for the printing of wool by the so-calledVigoureux printing process.

The following examples serve to illustrate the invention withoutlimiting it in any way. Where not otherwise and the mixture turns red.After stirring for 6 hours, it is diluted with 2000 parts of hot water,200 parts of sodium chloride are added and the red dyestuif which hasprecipitated is drawn off under suction, washed on the suction filterwith a 2% aqueous solution of sodium chloride until the reaction isneutral and dried at 80.

The brownish-red dyestuff dissolves in hot water with a yellowish-redcolour and dyes wool from a boiling bath containing ammonium sulphate inlevel, pure, very fastto-light yellowish-red shades.

The following Table 1 contains some similar monoazo dyestufis which areproduced in the same way and which also dye wool in fast to light shadesfrom a neutral to weakly acid bath: column 1 shows the diazo componentssol-N and column 2 the azo components used. Column 3 gives the shade ofwool dyeing from a neutral to acetic acid bath.

Table 1 N 0. Parts Diazo component Parts Azo component Colour of wooldyeing 36. 6 2 amino 3.4 tetramethylene 1.1 di 32. 8 2 amino 8hydroxynaphthalene 6 -sul Yellowish red.

phenyl disulphimide. phonic acid-N -methyl-N-phenyl amide. 36. 22-aminophenyl-2'-naphthyl disulphimide- 32. 8 .--..d D0. 36. 2 do 29. 42 amino 8 hydroxynaphthalene 6 sul Do.

phonic acid-N.N-diethyl amide. 34.7 2 amino 4 chloro 1.1 diphenyl disul35. 6 2 amino 8 hydroxynaphthalene 6 sul Do.

phimide. phonic aeid-N-ethyl-N-o-tolyl amide. 38.1 2 amino 3.4 dichloro1.1 diphenyl 34. 2 2 amino 8 hydroxynaphthalene 6 sul Do.

disulphimide, phonic aeid-N-ethyl-N-phenyl amide. 38. 1 do 40.6 2-amin0-8-hydroxynaphthalene -6-sul- Do.

phonic acid-N -meth yl-N (4'' -methyl sulphonyl phenyl)-amide. 7- 38. 12-amino-4.4-dichloro-1.l-diphenyl disnl- 32. 8 2 amino 8-hydroxynaphthalene 6 sul Do.

himide, phonic aeid-N-methyl-N-phenyl amide. 8---. 39. 4 2-amino-4-trilluoro -methyl-4' -methyl- 32. 8 d0 Red.

1.1-diphenyl disulphimide. 9.-.. 41.82-amino-4-ethyl-sulphonyl-4-methyl- 32.8 .-..-d0 D0.

1.1-diphenyl disulphimide. 10-" 38. 3 2 amino 5 acetyl amino 4 methyl32.8 ..-.-d0 D0.

1.1-diphen l disulphimide. 11-- 44. 5 2-amino-5- enzoyl-amino-4-methyl-32.8 .----d0 D0,

1.1-diphenyl disnlphimide. 12'." 36. l 2 amino 4 methyl 4 chloro -1.1 di32. 8 ----d0 Yellowish red.

phenyl-disul'phimlde. 1 49. 7 2-amino-4-sulphonlc acid-N-ethyl phenyl32. 8 ...-.d0 Do.

aniade-y-methyld.1-diphenyl disulphim e. 14" 46. 6 3 amino 4 (ptolylsulphonyl) 1.1' -di- 31. 0 2- amino -8- hydroxynaphthalene B-sulRed.

phenyl disulphimide. phtizic acld-N-ethyl-N.fl-hydroxy-ethyl am e. 41. 62 amino 5.2'.5' trichloro 1.1 diphenyl 31. 0 ..-..d0 Do,

disulphimide. 16-- 32. 6 2-ami110-4-methyl-1.1-diphenyl dlsulphl- 40. 22 ammo 8 hydroxynaphthalene 6 sul- Do.

mide. phonic acid-N.N-dicyclohexyl amide. 40. 5 2 amino 4 methylsulphonylamino 1.1- 40. 2 .--.d0 Do.

diphenyl disulphimide. 1 40. 2 amino 4 chloracetylamino 1.1 di 32. 82-am1no-8-hydroxynaphthalene-6-su1- Do.

phenyl disulphimide. phonic acid-N-methylphenyl amide. 19-" 39. 1 2amino 3 suliamido 1.1 diphenyl 40. 4 2-amino -8 -hydroxynaphthalene-6-sul- D0.

disulphimide. phonic acid-N-benzyl-N-phenyl amide. 0"- 39. 0 2 amino 4methyl sulphonyl 1.1 di 40. 4 Do.

phenyl disulphimide. 21-- 42. 2 amino 4 chloro 4 methylsulphonyl 37. 0 2amino 8 hydroxynaphthalene 6 sul Do.

1.1-diphenyl disulphimide. phonic aeid-N-butyl-N-phenyl amide. 22---43.1 2 amino 3 benzoylamino 1.1 di 30.82-amino-8-hydroxynaphthaleno-6-sul- Do.

phenyl disulphimide. phonic acid morpholide. 23.-. 43. 1 do 29. 4 2-amino 8 -hydroxynaphthalen'e 6 -sul Do,

phonic acid-N.N-diethyl amide. 4. 40. 4 3 amino 4 methyl sulphonyl 4meth- 37.0 2 amino 8 hydroxynaphthalene 6 sul Do.

yl-1.1-diphenyl disulphimide. phonic acid-N-butyl-N-phenyl amide. 5- 54.4 3-amino-4-(4"-methylbenzene sulphonyl)- 32. 8 2 amino 8hydroxynaphthalene 6 sul Bluish red.

4 methyl sulphonyl 1.1 diphenyl phonic aeid-N-methyl-N-phenyl amide.disulphirnide. 47. 7 3 amino 4 methyl sulphonyl 4 car 32. 8 d0 Do.

bethogyamino 1.1 diphenyl disulphi 32.6' parts ofZ-amino-4-methyl-l.l'-diphenyl disulphimide in the form of the sodiumsalt are dissolved in 1000 parts of water, 6.9 parts of sodium nitriteare added and the 40 warm solution is added dropwise to 30 parts ofconcentrated hydrochloric acid and 100 parts of ice at 0 to 8. Afterstirring for one hour at 0 and decomposition of some excess nitrousacid, the colourless diazo suspension is poured into a solution of 34.2parts of 2-amino-8-hydroxynaphthalene-6-sulphonic acid-N- ethyl-N-phenylamide in 300 parts of glacial acetic acid and 500 parts, of ethanol.

38.1 parts of 2 amino 4.4 dichloro 1.1 diphenyl Coupling occursimmediately disulphimide in the form of the sodium salt are dissolveddecomposed. 'The diaZQ suspefisiolll' in-1000 pattsof hot water; 6.9parts of sodium nitrite are added-and the solution is. added dropwise at.0.5 while stirring and externallycooling; onto a mixture of 30 parts ofconcentrated hydrochloric acid and 100' parts of ice. The colourlessdiazo suspension is stirred for 1 hour at -55 and then a*litt le exce ssnitrous acid is p a V is slowly poured while stirring at 0-10"intoa-solution ofll29 .5 parts of 2-amino-6-naphthyl-4;methyl phenylsulphon'e dissolved in 500 parts of glacial acetic acidarid fiw'parts ofethanol. Coupling occurs quickly and the-colour becomes orange.

After stirring for 8 hours at 0-10, the temperature is raised to 60,2000 parts of hot water are added and the acid is neutralised to someextent by sprinkling in 80 parts of sodium chloride. The dyestutf isprecipitated in the form of the sodium salt with sodium chloride,filtered off under suction, well washed with sodium chloride solutionand dried.

The orange dyestufl dissolves in hot water and dyes wool fromlaneutralto weakly acid bath in pure orange, fasttolight shades,

The 2-amino-6 naphthyl-4'-methyl phenyl sulphone is obtained in thefollowing manner: 1.2 mols of pulverised aluminium chloride are added insmall portions at usual temperature to a solution of 2-nitr0naphthalene-6-sulphochloride in excess abs. toluene. After heating for4 hours on a water bathat 70 the development of hydrochloride ispractically complete. Ice and.hydrochloric acid are added and the excesstoluene'is removed with steam. After cooling, the residue is filteredunder suction, .the filter residue is washed with water, dried at 100and recrystallised from alcohol.

The following Table 2 gives further examples of similar monoazodyestuffs which are producedaccording to the;

34.7 parts of 2-amino-4'-chloro-1.1-diphenyl disulphimide in the form ofthe neutral sodium salt are dissolved in 1000 parts of water, 6.9 partsof sodium nitrite are added and the warm solution is added dropwise to30 :parts of hydrochloric acid -and-l00 .parts off-ice at 0 5. 'Afterstirring for 1- hour at 0- and decomposing a little excess nitrousacidQthe'coIourIeSs diazo suspension is poured into a solution-of 29.9parts of -2-aminonaphthalene-7-sulphonic acid phenol ester in 300partsof glacial acetic acid andSOOiparts of ethanol. Coupling'occurs'immedia'tely and thecolour becomes orange. The coupling mixtureis stirred for 6 hours, theudiluted with 2000 parts of hot water, 100parts ofl'sodium chloride are added and the precipitated .orangedyestuifis filtered off. It is washed neutral on the suction filter. with 2%sodium chloride solution and then dried'at The yellowish-brown dyestuifdissolves in hot water withvan orange colour and dyes wool on boiling ina 'bathcontaining ammonium sulphate in level fast to light orangeshades.

The azo component used is obtainedfrOmZ-nitronaphthalene-7-sulphochloride" by reactingwith phenol whilestirring strongly in phenolphthalein alkaline/aqueous solution (pH of.the; solution 9-11) in the warm andreducing the nitro group tothe'aminogroupJ The following Table.3 contains some further similarmethod described in Example 2 andwhich dye wool from 35 mondazodyestuifsproduced by the 7. method, described a neutral to weakly acid bath infast to light shades also "in Example 3 which have ,similanpr'operties};I, l

TableZ 7 No; Parts. Dia zo component v Parts Azo component .Colour ofwool. :4 1 i dyeing 1.--. 38. 1 2 amino 3'31 dichloro 1.1 diphenyl 28. 32-- amino 6 naphthyl phenyl sulphone Orange. dlsulphimlde. a 2....- 32.6 2 amino 4' methyl 1.1 diphenyl dl 31. 8 2 amino 6 naphthyl 4chlorophenyl Do.

sulphimide 7 phone. 3. 32.6 do i 29.7 z-alrlnifiofl-naphthyl-4-methylphenyl Do.

' s p one. 4.--.-- 38. 2 2 amino 5 acetyl amino 4 methyl 29. 7 do Do.

1.1 dlphenyl disulphimide. l 5 40.4 2 amino -.4 methyl sulphone 4 31. 12 amino 7 naphthyl 3'11 dlmethyl Do.

methyl 1.1 diphenyl disulphimide. phenyl sulphone. 6 34.7 2 amino -.4chloro 1.1 dlphenyl 31.3 2- amino 8- hydroxy 6 -naphthyl -4 Red.

disulphimide. methyl phenyl sulphone. 7--..- 38.1 2 amino 3C4 dichloro1.1 diphenyl 31. 3 do Do.

disulphimide. 8. 36.1 2 amino 4 methyl 4 chloro -.1.1 .22. 1 2-amtno -5-naphthyl-methylsulphone Orange diphenyl disulphimlde. 9 32. 6 2 amino-.4 methyl 1.1 diphenyl 29.7 2-amino-5-naphthyl-4 -methyl phenyl Do.

disulphimide. 'sulphone. 10-.- 34. 7 2 amino 4 chloro 1.1 dlphenyl di-29. 7 2 1 amino 5 napthyl 4 methyl phenyl Do.

sulphtmide. 'sulphone. 11 43.1 2 amino 4 benzoylamlno 1.1 d1 22.1Z-amino-5-naphthylmethy1su1phone Do. phenyl disulphimide. 12--- 39.9 2amino 4 carbethoxyamino 1.1 23.5 2-amino-7-naphthyl ethyl sulph0ne- Do.

diphenyl dlsulphimide.

.. Table 3 No. Parts "Diazo'component Parts .azo component Colour ofwool r dyeing 1---. 34. 7 2-amlno-4-chloro-1.1-d1phenyl disulphi- 33.4Z-amlnonaphthalene-B-sulphonie aeid-4- Orange.

mide. T chlorophenol ester. p 2---- 34. 7 do 31.3Z-amlnonaphthalene-G-sulphonic acld-4- Do.

1 methyl phenol ester. v 3---- 34.7 Vdo 31.32-aminonaphthalene-5-sulphonic acid-4"- Do.

methyl phenol ester. 4---- 34. 7 do 35. 62-aminonaphthalene-fi-sulphonie acid-4- Do. tert. butyl phenol ester.

5- 34. 7 do 32. 9 2 amino 8 hydroxynaphthalene 6 Yellowish red.

7 sulphonic acid-4-methyl phenol ester. 6---- 38.82-amino-5-acetylamlno-4-methyl- 1.1-di- 31.52-an1ino-S-hydroxynaphthalene-G-srfl- Do. phenyl disulphimide. phonleacid phenol ester.

7--.. 41. 8 2-amino-4 -ethyl -sulphonyl-4-methyl- 36. 92-aminonaphthalene-6-sulphonic aeid-3'.4'- Orange.

1.1-diphenyl dlsulphlmide. dlchlorophenol ester. r

7 EXAMPLE 4 36.1 parts of 2-amino-4-methyl-4-chloro-1.1-diphenyldisulphimide in the form of the neutral sodium salt are dissolved in 500parts of hot water, 6.9 parts of sodium nitrite are added, the solutionis cooled to about 40 and then added dropwise at 8 to a mixture of 30parts of .concentrated hydrochloric acid and 100 parts of ice whilestirring and externally cooling. The colourless diazo .suspension isstirred for an hour at 0-5 and then a little excess nitrous acid isdecomposed. The diazo suspension is then slowly poured while stirringat010 into a solution of 32.6 parts of 2-aminonaphthalene-6- sulphonicacid-N-ethyl-N-phenyl amide dissolved in 300 parts of glacial aceticacid and 500 parts of ethanol. Coupling occurs quickly and the colourbecomes orange. After stirring for 8 hours at 0-10", the temperature israisedto 50, 1000 parts of water are added and the acid is partlyneutralised by sprinkling in 100 parts of sodium carbonate. The dyestuifis precipitated with the aid of sodium chloridelas the sodium salt, itis filtered under suction, washed well with 5% sodium chloride solutionand dried.

The orange dyestuif dissolves well in hot water and dyes wool from aneutral to weakly acetic acid bath in pure orange fast to light shades.

The following Table 4 contains some further monoazo dyestuffs which areproduced with the number of parts given of the components according tothe method described in Example 4. These dyestulfs have similarproperties. 7

of ammonium sulphate in 3000 parts of water. The bath is brought to theboil within minutes and boiled for 1 /2 hours while moving the woolwell. The Wool is then rinsed and dried. In this way, a very level,pure, yellowish-red wool dyeing is obtained which isdistinguished byvery good fastness properties.

The dyestuffs obtained according to all the other examples can be dyedon to wool in a similar manner.

What I claim is:

1. A monoazo dyestufi which is free from sulphonic acid and carboxylicacid groups and corresponds to the formula:

wherein A represents a radical selected from the group consisting of thebenzene and naphthalene series,'B represents a benzene radical which is'bound to the azo linkage in ortho-position relative to a sulphonylgroup, X represents a member selected from the group consisting of H andOH, and Y represents a sulphonyl substituent selected from the groupconsisting of --SO -alkyl, SO -[mononuclear carbocyclic aryl], -SOO-[mononuclear carbocyclic aryl] and SO R radicals, wherein R representsa secondary amino group.

2. A monoazo dyestufi which is free from sulphonic acid and carboxylicacid groups and corresponds to the formula:

consisting of the benzene and naphthalene series, B represents a benzeneradical, the bonds sown being in 0- Table 4 No. Parts Diazo componentParts Azo component Colour of wool dyeing 1--.- 38.1 2-amino-4.4'-dichloro-Llv diphenyl disul- 32.6 2-aminonaphthalene-S-snlphonie aeid-N-Orange.

p imide. ethyl-N-phenyl amide. 2.--. 36.2 2-aminophenyl-2-naphthyldisulphimide. 31.0 2aminonaphthalene-S-sulphonic acid-N- Do.

ethyl-N.B-hydroxyethyl amide. 3 44. 5 2-amino-5-benzoylami.uo-4methyl-l.1- 31.2 2-aminonaphthalene-7-sulphonic acid-N- 'Do.

diphenyl disulphimide. methy1-Nphenyl amide. 4 38.12-amino-3.4-diehloro-1.1-dipheny1disul- 31.2 do Do.

phimide. 5 38.1 do 27.8 2-aminonaphthalene-7-sulphonlc acid-N. Do.

N-diethyl amide. 6---. 38.1 do 38.9 2 aminonaphthalene-S-sulphonicacid-N- Do.

metgyl-N-p-methyl sulphonyl phenyl am a. 7 38.1 do 31.22-aminonaphthalene5-sulphonic acid-N- Do.

. methyl-N-phenyl amide. 8 46.6 3-amino-4.p-toluylsulphonyl-1.1-diphenyl31.2 do D0.

dlsulphimide. 9---- 41.8 2-amino-44athylsu1phonyl-4 methy1-1;1- 31:2 doDo.

diphenyl disulphimide. V 10--- 31.12-amino-4-su1phamido-1.1-diphenyldisul- 30.82-aminonaphthalene-7-sulphonic acid-N- Do.

phimide. benzyl-N-phenyl amide. 11--- 40.4 a-aminot-methyl sulphony1-4-methyl 38. 8 do D0.

1.1 -diphenyl disulphimide. 12 40.4 do 38.62-amin0naphthalene-fi-sulphonic acid-N. D0.

- -N-dlcyclohexyl amide. 13--. 47.7 3-amino-4-methylsulphonyl-4-carbethoxy- 27. 8 Zaminonaphthalene-5-sulphonic acid-N. Do.

am1n0-1.1-diphenyl disulphimide. N-diethyl amide. 14-" 40. 35 2-amin0-4-ch1oroacetylamino-1.1- 'phen- 29. 22-aminonaphthalene-7-su1phonicacldmor- Do.

yl disulphimide. pholide. 15--. 43. 12-amino-3-benzoylamlno-1.l'-diphenyl.di- 29. 2 do D0.

sulph'unide.

EXAMPLE 5 100 parts of previously well wetted wool are entered at 40into a dyebath containing 2 parts of the monoazo dyestuff obtainedaccording to Example 1 and 5 parts position to each other, X representsa member selected from the group consisting of H and OH, and Rrepresents the radical of a secondary amino group.

3. A monoazo dyestufi which is free from sulphonic 10 acid andcarboxylic acid groups and corresponds to the 6. The monoazo dyestufiwhich corresponds to the forformula: mula:

NH IIIH A-sr-NE-so,-B N= rQ-SOrNH-SO: N=N

X R 6 Ho 02115 1 l so 7 EN Oz-N z- 10 Arc-O C 2 J l; wherein Arepresents a radical selected from the group 7. The monoazo dyestutlwhich corresponds to the for- 3 consisting of unsubstituted and chlorinesubstituted and mu1a methyl substituted radicals of the benzene series,B represents a benezene radical, the bonds shown being in o- 5 IITHBposition to each other, X represents a member selected from the groupconsisting of H and OH, R1 represents a lower alkyl radical and Rrepresents a phenyl radical.

4. The monoazo dyestufi which corresponds to the formula: ON CH 1 NH, ENl I 01 sorNH-sm N=N (JO-O 8. The monoazo dyestufi which corresponds tothe for- 1 so,-N mula: l I III-H2 1 3 Q 01 -s0,-NH-s0, 1 r= 5. Themonoazo dyestuflz which corresponds to the 1 O gsormofia formula:

ObOSOrNH-SO: N=N- H0 0 H References Cited in the file of this patent 1so N 5 UNITED STATES PATENTS r 1,749,836 Neelmeier et a1 Mar. 11, 1930 O1,903,599 Schweitzer Apr. 11, 1933 2,358,519 Krebser etal Sept. 19, 1944

1. A MONOAZO DYESTUFF WHICH IS FREE FROM SULPHONIC ACID AND CARBOXYLICACID GROUPS AND CORRESPONDS TO THE FORMULA: